Versions X and Y of a DLL will be flat-out incompatible if that DLL is written in C++ and the author has changed the number of attributes in an interface class ....

Why would any developer do that? Why not create a new class with the added bits, and make the old class use the new one, passing in default values for the additions. That is backwards compatibility.

And the fact that Microsoft is so good at preserving application backward compatibility

Not for 3rd-party application code (which is nothing to do with them), but for the Windows OS code used by applications. And, from what I've heard, a lot of the "difficulties" here have been because Microsoft has lots of undocumented calls (so that MS products can do things that others "can't") which then non-MS applications start to use in other ways. If MS did have a fully-documented OS interface there might be fewer "poor practices". So it's self-inflicted, I fear.

An alternative view is that Symantec only reckon you are at risk if you use IE and that if you are using something else then you're already safe and hence of no interest to them?

Your biggest problem isn't filesystem compatibility, but id compatibility. For transfer between system I don't control I use tar files onto fat32, then extract at the other end. Or zip files if I think a non-standard based system such as MS Windows might be involved. For ones I do control, they are all Linux, so ext3. And I have the same uid/gid across them (so I use the same one at home (and teh same account name) as I have been allocated at work.

IANAL, but what about making it a licence fee?

You can pay Microsoft any amount of money but you have no rights at all over the software they give you except to use it as Microsoft says you may. And you don't own it in any way.

Such as copyrighted material which is legally downloadable in some parts of the world but not in the US?

No - such as on-line gambling. The US has it's own strictures, just as Iran and China do.

http://ieaddons.com/ [ieaddons.com]

They all seem to be about fetching content - not about adding functionality. The only extension I have ever used on IE is iehttpheaders, and it doesn't get a mention. Can anyone create extensions to be added here, or would you have to pay Microsoft to host it?

XP is also out of date. In fact, isn't in now more expensive to put XP onto a system rather than Vista? This decision will save money over 10 years? Compared to what? It doesn't mention how much other options might have saved.
I just hope they don't put Windows in submarines.

"Teach both. You know, don't be afraid of information. Healthy debate is so important, and it's so valuable in our schools. I am a proponent of teaching both."

OK - but not in the Science class. Politics, Religion or Sociology classes would be OK. Presumably she is equally keen for Atheism, Druidism and Witchcraft to be taught? Oh, no - wait - she's in the US, so you have to keep religion out of school.